A heat exchange system, which includes a unified heat exchanger that enables heat exchange between fluids of different types, is known (see, for example, JP3275415B2, or JP4311115B2 (corresponding to US20040060316A1).
Specifically, JP3275415B2 teaches a heat exchange system that includes a unified heat exchanger having a heating heat exchanging arrangement and a heater core, which are integrated together. The heating heat exchanging arrangement exchanges heat between refrigerant (first fluid), which is outputted from a compressor, and conditioning air (subject heat exchanging fluid) to be blown into a vehicle cabin to heat the conditioning air. The heater core exchanges heat between brine (second fluid), which is heated by a water heater of a combustion type, and the conditioning air (subject heat exchanging fluid) to heat the conditioning air.
JP4311115B2 (corresponding to US20040060316A1) teaches a heat exchange system, which includes a unified heat exchanger having the heating heat exchanging arrangement and a heater core, which are integrated together. The heating heat exchanger is similar to that of JP3275415B2. The heater core of JP4311115B2 (corresponding to US20040060316A1) exchanges heat between engine coolant (second fluid), which cools the engine, and the conditioning air (subject heat exchanging fluid) to heat the conditioning air.
However, JP3275415B2 and JP4311115B2 (corresponding to US20040060316A1) merely teach the heat exchange system, which heats the subject heat exchanging fluid by releasing the heat of the first or second fluid (the refrigerant, the brine or the engine coolant), which has the temperature higher than that of the subject heat exchanging fluid, at the unified heat exchanger to heat the subject heat exchanging fluid. Specifically, the heat exchange system of JP3275415B2 or JP4311115B2 (corresponding to US20040060316A1) functions only as the heating heat exchanger, which heats the subject heat exchanging fluid by the heat of the first or second fluid, and does not have a function of adjusting the temperature of the subject heat exchanging fluid, so that the temperature of the subject heat exchanging fluid cannot be adjusted to a desired temperature.
Furthermore, in a previously proposed vehicle refrigeration cycle system, which is applied to a vehicle (e.g., an electric vehicle or a hybrid vehicle) that does not have a dedicated heat source for heating a vehicle cabin, an indoor heat exchanger is used to cool or heat cabin conditioning air to be blown into the vehicle cabin. Specifically, at the time of cooling operation of the vehicle cabin, the indoor heat exchanger is used as an evaporator to cool the cabin conditioning air. At the time of heating operation of the vehicle cabin, the indoor heat exchanger is used as a radiator to heat the cabin conditioning air. This switching of the operation of the indoor heat exchanger between the cooling operation and the heating operation is achieved through switching of a flow of refrigerant in the cycle.
However, at the time of switching the operation from the cooling operation to the heating operation (at the time of switching the function of the indoor heat exchanger from the evaporator to the radiator), droplets of water (dew), which adhere to an outer surface of the indoor heat exchanger, are evaporated to cause an increase in a humidity of the cabin conditioning air, and the cabin conditioning air having the high humidity disadvantageously causes window condensation (condensation of moisture on a window glass) in the inside of the vehicle cabin.
In order to address such a disadvantage. Japanese patent JP3538845B2 (corresponding to U.S. Pat. No. 5,299,431A) teaches placement of an evaporator, which evaporates low pressure refrigerant, and a radiator, which radiates heat of high pressure refrigerant, in a casing that conducts the cabin conditioning air to be blown into the vehicle cabin. The radiator is used to heat the cabin conditioning air, and the evaporator is used to cool the cabin conditioning air. That is, according to Japanese patent JP3538845B2 (corresponding to U.S. Pat. No. 5,299,431A), the radiator, which heats the cabin conditioning air, and the evaporator, which cools the cabin conditioning air, are separately provided in the casing, so that the blowing of the cabin conditioning air having the high humidity into the cabin at the time of switching from the cooling operation to the heating operation is advantageously limited.
Here, it should be noted that in some cases, a temperature of first subject heat exchanging fluid, which is used to adjust a temperature of a first temperature adjusting subject, and a temperature of second subject heat exchanging fluid, which is used to adjust a temperature of a second temperature adjusting subject, are adjusted in the vehicle refrigeration cycle system.
For instance, a temperature of front seat side conditioning air to be blown into a front seat side space of the vehicle cabin and a temperature of rear seat side conditioning air to be blown into a rear seat side space of the vehicle cabin may be adjusted in the vehicle refrigeration cycle system. Alternatively, a temperature of the cabin conditioning air to be blown into the vehicle cabin and a temperature of heating medium, which adjusts a temperature of a subject operational device in the vehicle, may be adjusted.
In such a case, the vehicle refrigeration cycle system needs to have a second heat exchanging mechanism, which adjusts the temperature of the second subject heat exchanging fluid, in addition to the first heat exchanging mechanism (e.g., the evaporator and the radiator), which adjusts the temperature of the first subject heat exchanging fluid.
However, when the vehicle air conditioning system of Japanese patent JP3538845B2 (corresponding to U.S. Pat. No. 5,299,431A) is applied to such a structure, it is required to provide the evaporator and the radiator to each of the first and second heat exchanging mechanisms. Therefore, it may be difficult to have a sufficient installation space for installing the vehicle refrigeration cycle system in the vehicle, thereby resulting in deterioration in installability of the vehicle refrigeration cycle in the vehicle.